Phonograph record



Sept. 24, 1929. GUERNSEY 1,728,932

PHONOGRAPH RECORD Filed NOV. 25, 1927 INVENTOR cfoh nE'. Guernsey ATTORNEYS Patented Sept. 24, 1929 UNITED STATES JOHN E. GUERNSEY, OF INDIANAPOLIS, INDIANA PHONOGRAPH RECORD Application filed November 25, 1927. Serial No. 235,527.

My invention relates to sound records and particularly to the disc type of record.

It is one of the objects of my invention to provide a record having an auxiliary groove in the face thereof for causing a movement of the tone arm of the reproducing machine, which movement may be utilized to operate mechanism which will stop the action of the apparatus or return the tone arm to initial position and permit a repeating action.

In the drawings forming a part of the accompanying specification,

Fig. 1 is a plan view of a record embodying my invention, and

Fig. 2 is a partial sectional view on the line 22 of Fig. 1.

As shown in the drawings, the disc record 1 is provided with the usual spiral sound record groove 2, in the annular space 3, ending considerably short of the center so as to leave the circular space 4 surrounding the central opening 5.

Connecting with the inner end of the record groove 2, and extending into the space 4; is the groove 7 which is the characteristic feature of my invention. Groove 7 starts in the sound reproducing groove but has a quicker pitch and preferably ends in a circular or continuous groove 8. The curvature of groove 7 is such that at the point 9 the groove is closer to the center opening of the record than at its starting point. From this point 9 the curve is such that at the point 10 the groove is more remote from the center of the record and preferably not as distantly spaced as at its starting point. From the point 10 the curve then spirals inwardly toward and merges into the groove 8 so that that portion 11 of the groove will cause the tone arm to move nearer to the center of the disc than did portion 9 of the groove.

As the needle of a tone arm of a phonograph traverses groove 7 the tone arm'will first move rapidly inward; this movement will then be followed by an outward movement which will then be followed by another inward movement the radial extent of which will be greater than the first movement. This reciprocating movement will preferably occur within one complete rotation of the disc and may be utilized to control apparatus by which rotation may be stopped or permitted to continue, the tone arm may be returned to position for repetition, the record may be changed, etc.

I claim as my invention:

1. A sound record provided with a record groove and an auxiliary spiral groove continuing beyond the inner end of the record groove and so formed as to cause the tone arm of a reproducer to be moved toward the center of thedisc, then away from the center of the disc and then toward the center of the disc a distance greater than the initial movement toward the center of the disc.

2. A sound record provided with a spiral sound record groove and an auxiliary groove, said auxiliary groove continuing beyond the end of the sound record groove and comprising a compound curve, one portion of said curve approaching the center of the record, a succeeding portion of said curve receding from the center of said record and a succeeding portion of said curve approaching the center of a record a greater distance than that of said first mentioned portion.

In witness whereof, I have hereunto set my hand at Indianapolis, Indiana, this 22nd day of November, A. D. one thousand nine hundred and twenty-seven.

JOHN E. GUERNSEY. 

